Further revelations from the book Dirty Politics suggest Cameron Slater's Whale Oil blog was used to discredit an organisation that arranges fair working conditions and training for office cleaners - some of New Zealand's poorest workers.
The book by Wellington writer Nicky Hager claims that following a smear campaign on the site, an agreement that government buildings could be cleaned only by companies which met certain standards for workers was scrapped.
Building Service Contractors (BSC) is the industry body for commercial cleaning companies which, under the last Labour-led government, made a deal with the Food and Service Workers' Union to improve training and conditions for office cleaners.
Under the deal, companies could win contracts to clean government offices only if they became members of BSC and pledged to improve working conditions.
Mr Hager's book suggests posts that began appearing on the Whale Oil blog criticising the BSC Contractors in 2012 were organised by public relations man Carrick Graham on behalf of Crest Commercial Cleaning, which could not bid for government contracts because it was not a member of BSC.
BSC's national president Patrick Lee-Lo says the raft of personal attacks and claims that he wasted membership fees have taken their toll.
"I've got two daughters and they were in my office one day and saw all the blog comments on my desk because someone had kindly sent them (and in fact to all our members). They were extremely upset and asking me to step aside from being president, because it's not a paid role, I do it voluntarily and they said: 'You don't need this stuff Dad.'"
Crest Commercial Cleaning managing director Grant McLauchlan says any claim that a campaign through Whale Oil influenced the Government's decision to open contracts up to non-BSC members is ridiculous.
"We have not specifically paid Carrick Graham to run a smear campaign on Whale Oil," he said.
Grant McLauchlan admits public relations work was done for him by Mr Graham against Mr Lee-Lo and the BSC, but it was through the mainstream media and public channels including submissions to the Government.
Mr Graham declined to be interviewed by Radio New Zealand.
The Service and Food Workers' Union national secretary, John Ryall, says when the union was told that the agreement between the Government and cleaning companies would be scrapped, it knew something was awry.
"We got informed at 4.30pm on the 29th of May. We didn't actually find out until later that Whale Oil was running the announcement at 4pm and so there is a direct connection, as far as we are concerned, and something very suspicious how Whale Oil got informed of this prior to the parties that are involved in this agreement."
Cameron Slater declined to comment, saying he doesn't give interviews to Radio New Zealand.
Mr Lee-Lo says he will be seeking legal advice on whether to pursue the matter.